1. Technical Field
The technical field relates to the operation of motor vehicle transmissions, and in particular, to a method for dynamic adaptation of shift schedules used with automatic transmissions to support diverse performance objectives.
2. Description of the Technical Field
Contemporary motor vehicles typically provide control modules for major vehicle sub-systems and one or more communication channels over which data are exchanged between the control modules. Vehicles having an internal combustion engine and transmission sub-systems are typically provided with an engine controller/engine control unit (ECU) and a transmission control module (TCM). The communication channels are usually a physical data bus such as a twisted wire pair provided as part of a controller area network (CAN). Overall vehicle fuel economy and driving performance has been enhanced by the cooperation in controller operation using networking technology such as CAN.
Conventionally, transmission control software has been installed on the TCM. Transmission control software includes shift control logic (SCL) which has access to a plurality of shift schedules. Shift schedules operate on vehicle operating variables, particularly engine speed and vehicle speed, to select a transmission gear within an allowed range and to control shifting to the selected gear. On vehicles equipped with “automatic manual transmissions,” clutch control logic (CCL) implements engagement and disengagement of the transmission clutch(es). The SCL selects a shift schedule based on selected performance objective (for example economy, performance) and a gear ratio from those available according to the shift schedule. The timing of shifts to the selected gear ratio occur in coordination with the CCL whereby the selected gear becomes the achieved gear.
Shift schedules have been supplied by transmission original equipment manufacturers based on base engine performance characteristics. The shift schedules have been particular to a specified vehicle and engine combination on a vehicle.